use serde::de;
use snafu::{IntoError, NoneError as NoSource, Snafu};

use crate::{Error as DataStoreError, ScalarError};

/// Potential errors from deserialization.
#[derive(Debug, Snafu)]
#[snafu(visibility(pub))]
pub enum Error {
    // This error variant is required to implement ser::Error for serde.
    #[snafu(display("Error during deserialization: {}", msg))]
    Message { msg: String },

    #[snafu(display("Error deserializing scalar value: {}", source))]
    DeserializeScalar { source: ScalarError },

    #[snafu(display(
        "Data store deserializer must be used on a struct, or you must give a prefix"
    ))]
    BadRoot {},

    #[snafu(display(
        "Removal of prefix '{}' from key '{}' failed: {}",
        prefix,
        name,
        source
    ))]
    StripPrefix {
        prefix: String,
        name: String,
        #[snafu(source(from(DataStoreError, Box::new)))]
        source: Box<DataStoreError>,
    },

    #[snafu(display("Prefix '{}' is not a valid key: {}", prefix, source))]
    InvalidPrefix {
        prefix: String,
        #[snafu(source(from(DataStoreError, Box::new)))]
        source: Box<DataStoreError>,
    },
}

pub type Result<T> = std::result::Result<T, Error>;

impl de::Error for Error {
    fn custom<T: std::fmt::Display>(msg: T) -> Self {
        MessageSnafu {
            msg: msg.to_string(),
        }
        .into_error(NoSource)
    }
}